Twenty-five years ago, U.S. tech companies pledged to stop using chemicals that caused miscarriages and birth defects. They failed to ensure that their Asian suppliers did the same.

The women on the production line worked in so-called cleanrooms and wore protective suits, but that was for the chips’ protection, not theirs. The women were exposed to, and in some cases directly touched, chemicals that included reproductive toxins, mutagens, and carcinogens. Reproductive dangers are among the most serious concerns in occupational health, because workers’ unborn children can suffer birth defects or childhood diseases, and also because reproductive issues can be sentinels for disorders, especially cancer, that don’t show up in the workers themselves until long after exposure.